Leveling mechanism for hydraulically actuated press brakes



July 15, 1952 DREls 2,603,145

LEVELING MECHANISM FOR HYDRAULICALLY ACTUATED PRESS BRAKES Filed April 25, 1950 4 Sheets-Sheet 1 19 v H 1 J0' \H M K.-

eo X61 \h i 80 a; Z; 6 6 e2 M835 July 15, 1952 E. M. DREIS 2,603,145

LEVELING MECHANISM FOR HYDRAULICALLY ACTUATED PRESS BRAKES Filed April 25, B50 4 Sheets-Sheet 2 v J0 J a4 ii V////////////// 5 fizdefZo/"r July 15, 1952 E M DREls 2,603,145

LEVELiNG MECHANISM FOR HYDRAULICALLY ACTUATED PRESS BRAKES Filed April 25, 1950 4 Sheets-Sheet 5 Jul 15, 1952 E. M. D s 2,603,145 LEvELIm MECHANISM HYDRAULICALLY ACTUATED PRESS BRAKES 4 Sheets-Sheet 4 Filed April 25, 1950 w\\\\\\ s Q j @4419 /\/-v9 5 5?; v Q

fiwzzow a aia WdJ/Z @y/Mf/TZ 3 the ram IS with respect to the housing II and the bed l3.

The hydraulic system The hydraulic system for supplying fluid under pressure to the cylinders l8 and |8a is best shown in the schematic view of Figure 7. A hydraulic reservoir or tank 2| has mounted thereon a pair of transversely spaced pumps 22 and 23. The pumps 22 and 23 are respectively driven by stub shafts 24 and 25. A common shaft 26 is mounted in bearings 26a, the shaft being rotated by means oi a V-belt pulley 21 which is driven by belts 28 from a pulley 29 rotated by a shaft 30 from an electric motor 3|. Between the ends of the shafts 26 and the stub shafts 24 and 25 electrically controlled mechanisms in the form of electric clutches 33 and 34 are provided. The clutches 33 and 34 are of a conventional type which ar normally energized in driving relation.

The type of clutch that may be utilized may be an electro-magnetic clutch that is normally clutching and may be electrically de-energized. Or it may be any mechanical or electrical clutch that can be electrically controlled to establish and tobreak driving relation with a power unit in response to a switch control.

Rectifiers 35 and 36 are respectively connected to the clutches 33.and 34. These rectifiers are a part of the conventional mechanism of a magnetic clutch assembly and need not be described in detail.

.The pumps 22 and 23 are connected by conduits 31 and 36 to relief valves 39 and 48. The cylinder |8a receives fluid under pressure from the pump 22 through a conduit 4| connecting the relief valve 39 with a conventional four-way valve 42. The valve 42 has a passage 43 which, in the position shown inFigure 7 is in communication through a conduit 44 with the upper end of the cylinder [8a, both the cylinders i8 and |8a being the two way pressure types.

The cylinder i8 receives fluid under pressure from the pump 23 through a conduit 45 which is in communication with a passage 46 in a fourway valve 41. The passage 46 in turn may be placed in communication with a conduit 48 in communication with the upper end of the cylinder i8.

The cylinder [8 has a conduit 48 in communication with its lower end, the conduit 48 being adapted to communicate with a passage 58 in the valve 42. The conduit 49 through the passage 50 is adapted to communicate with a conduit leading to the reservoir 2|. The cylinder |8a has its lower end in communication with a conduit 52 which is in communication with a passage 53 in the four-way valve 41. The passage 53 is adapted to communicate with a conduit 54 leading to the reservoir 2|. 1

The leveling mechanism The leveling mechanism is generally designated by the reference character 55. The mechanism 55 comprises a rack bar 55 which is carried by the ram l6 for reciprocation therewith. A second rack 51 is laterally spaced from the rack 56, the second rack being slidable in a wide slot or groove 58 extending vertically-in the ram I6. In other words the rack 51 can slide vertically in the slot 58 relative to the ram during movement of said ram iii. The slot 58 is sufiiciently wide so that theram I6 can tilt a certain degree without affecting the vertical position of the rack 51. A torque tube 58 is Journalled on the housing uprights l2 by bearings 60. A pinion 6| secured to the shaft 59 is in meshing engagement with the rack 56 and a pinion 62, secured to the shaft 58. is in mesh with the rack 51. It can be seen therefore that the rack 51 is supported and held in vertical relation by its engagement with the pinion 62 and is thus held in the vertical coordiri'ated relation with respect to the rack 56, independently of the sliding movement of the ram l6. The rack 51 is held in the slot 58 by means of the pinion 62 but the sliding movement of the ram at the point of contact with the rack 51, does not aifect the position of said rack. Thus the rack 51 may be termed as being independently supported free of the ram I 6.

Referring now particularly to Figures 4 and 7 a limit switch mechanism 63 is pivotally mounted on the ram 6 adjacent the rack 51. The switch 63 has upper and lower switch elements 64 and 65. The elements 64 and 65 are adapted to be engaged by a lug or trip plate 66 which may make or break the switch elements as will be explained in the operation. The switch element 64 is connected by suitable circuits 61 and 68 to a source of electricity as shown, and to the rectifier 36 which controls the clutch 34. The switch element 65 is connected to rectifier 35 by circuits 68 and 66 and to a source of electricity as shown. The electric motor 3| is connected by leads 10 to the wire 68 and to a wire 1| con-v trolled from a push button switch 12. 4 i i I Upper and lower switches 13 and 14 aremounted on the front face of the ram l6 as shown in Figure 1. These switches 13 and 14 are connected by leads 15 and 16 to the circuit as shown in Figure 7. Adjustable arms 11 and 18 are moveably mounted on a rod 13 the rod being suitably supported on a portion of the housing ii. The switches 13 and 14 may be opened and closed in a conventional manner by the arms 11 and 18, for limiting the vertical reciprocation of the ram IS.

The pivotal connection of the switch mechanism 63 is best shown in Figures 5 and 6 The switch mechanism 63 is supported by a plate connected to a shaft 8| extending through the ram l6. A link 82 is connected to the shaft 8| and the link 82 is connected to a reciprocating plunger 83 of a micrometer 84. The micrometer 84 may be of a conventional type and is pivotally connected to the ram l6 as indicated at 85. An adjusting sleeve 85a may be rotated for effecting reciprocation of the plunger 83 to secure in turn angular positioning of the plate 80 and switches 64 and 65.

The operation In the position shown in Figures 1, 2, and 7 the ram I6 is ready to begin downward movement. The 'motor' 3|. is set in operation by switch 12 and the shaft 26 begins rotation. ,The clutches 33 and 34 are in operative relation and the pumps 22 and 23 are actuated through stub shafts 24 and 25. Fluid under pressureflows through conduits 4| and 44 to the upper portion of cylinder 3a and likewise fluid under pressure flows. through conduits 45 and 46 to cylinder l8 causing the ram to move downwardly. Fluid at the lower end of the cylinders 8 and IM is returned respectively by conduits 49 and 5| and conduits 52 and 54 to the reservoir 2|.

. As the ram [6 is moving downwardly the rack 56 effects rotation of the pinion 6| thereby rotating the torque shaft 59. This rotation of shaft 59 reacts on rack 51 to keep this rack in attentimeans of -af'pivot-pin 56a' which ekt'endsthroug'h the Tram. In other words the 'r'acks 56 and 51 remain a sthstafitially vertical 'lahd pai'allel position espite tilting of theraii'i si-fice tl'i'y Kare held in thisj positioil by the 'pi nions filfefid 'fl. -ln afico nditionwherein thefcylfii'dr I818 'dp- Grating-faster than the Cylinder- [8a 'Itli'e' ram sprogressing -rurth r in its atwx'iwar pass'dn the side'havirig the -fidatihg 'or fsliding rack 51. Undr thiS Condition the i aek "56 is felatively stationary and 7 consequentl the torque b'a'r or snartss is locke'd'agains't rotation. 'The 'pinio'n GI -is thus heldagaihst movement-andthe rack B'I rerha'ins stationery or positioned" in the same' vertical-coordinated relation as the'r'ack'ifi. The rain "on theside of the cylinder l8- continues to -iriove and the switch fittherefore makes em gageiiient withthe 111g 68 whereupon the switch 64- is' actuated'to energize the rectifier 36 which turifpermits' the clutch 34 to slip 'withrespect to "the shaft 25 and pump 23. Less fiuid is therefore delivered from pump 23 to cylinder l8 and the pump '22 continues delivering fluid: pressure tocylinder I80. whereupon this retarded cylinder continues downward movement of the ram until a level position is reached. :When a lev'el position of the ram has been reached the switch'64 is again'retu'rned to its original pos'ition and the clutch 34 again transmits operating force to the pump 23 thereby actuating cylinder [8.

In aconditionwherein the cylinder l8a'operatesfaster and cylinder i8 is retarded the ram progresses faster on the side of the rack 55. In-thiscondition the rack-51 is maintained level with rack stand: since racktfi has moved downwardly with the rain IS, the rack 51 is in-a relatively-lower position with -respect' to the switch "65" whereupon the lug 66, engagesswitch 65*:to actuate the same. This causes the rectifier 35 to actuateathe clutch 33 to'slip causing relative-lesse'r delivery operation of thepuinpuntil cylinder [8 has caught up whereuponthe switch 6.5 is disengaged andnormal operationcontinues. Thus thelev'eling mechanism is eii'ectiveto keep the ram in -a level position since during any tilting movement the switches" react to control fluid deli-very to thecylinder that is advanced in operation. V r 1 Under certain operating conditions it'is desirablevto move the ram in a tilted or angular position. To-adjust the switch position angularly with respect to the ram, the operator need merely turn the-adjusting member 85a of the micrometer' 84 whereby theplatetil will be moved to the--desired position on the ram The switch mechanism 63 will then be positioned in proper angular relation to the rack 51 and the lug 66 so that the ram may be reciprocated in a tilted position, the leveling mechanism being effective to synchronize or coordinate the cylinders during any variance of the: rain from the desired tilted orang1ilar -po'sition duringreciprocation.

The downward movement of the" ram I B has beendescrihed. During upward moven'ient the Tv'alvef42 fisji sfhiftedsd that 'conduits"*'4 l andj49 erein communication through passage 50 whereupon f-piston'rod 1:9"is'inreved 'iil waralys- Flui'd fromthe upper end of cylinder 18a returns through conduits 44 passage 43 'iandxtconduit 5| 'to the tank 2|. The valve 41 is-moved fto place conduit 45 in communicationwith-conduit 52 throughpass'age 53 and cylinder .l 8 -is::.operated-to "move piston rod :upwardl'y; iiThe conduit 48 "is 'n'ow in 'communicationiiwith :con-- duit 54 through "passagelfi "and-'fluidireturns,

rrom cyiinder l 8""t0" the. tank" 2 l During the i'ipward "travel theficylinder? IB'a; is op erated b'ypum 23 and 7 cylinder." [8'- iszoperated by 22. This connection which; is

reverse to-the con'necti'onduring *downward movement of the' ram permits ."the operation .of the leveling 'niechanismwithout any, reversal of the fswitch mechani'sm or relocation ofnith'e. switches. If during "tilting of the :ram .du'ring upward 'trai el 'switch' 64 is engaged; the clutch 34 slips and fluid "delivery to" the cylinder 18a is controlled or' halted. .On the other-"hand if switch 65 is ac'tuated the clutch 233 slips :-:an'd cylinder I8 is controlled in its reception of fluid.

In Figures 7, 8, 9 and i0, safety switches '90 and 9| are provided'adjacent' the switchmechanisms 63. Theseswitches are in series with the electrical circuit and switch 12 in 'I-axsuitable manner to breakthe circuit to the clutches and the electric motor in the event that either of the switch'esi 64 "and'iifi are inoperative for any reason. The contact elements a; and. cm are p'os'itioned above' and belowthe" respective contacts' of the switches 64 and 'i Movement thereiore'of the contact plate 66 beyond either of "the" contacts of' the upper or lower? switches 64and 65-shuts offthe electrical system completely" thereby stopping all fluid flow T to-,the cylinders ls'an'd 18a.

Thus it can be seen that the level-travel of the ram is 'effectivelyass'ured bythe leveling mechanism during both upward" and downward travel of the ram. Thedegree of misalignment of an'g'ularityoi the ram'necessary to 'operate'the switches can he adjusted'toclose limits and the slidable rack "provides an effective simple rand positiveactuator'for theswitches. Equal travel of the extensibled'evices is thus maintained without' the use of a rigid mechanical. ram I control,

but with a"p'o'sitive mechanism for controlling fluid delivery. Y "The retarded cylinder or piston: is permitted to catch up while fluid control :is 6X61? cised over the advanced piston. One of the? prime features of the invention is exemplified innthe sliding rack and its novel cooperationwith the torque shaft and switches. The leveling device can be utilized 'in' -any construction where-level uniform travel of a part is necessary and 'the'part is actuated by a'plurality of-spacedipower units having a' tendency to operate 'ina non-uniform manner.

iIt is' realized that reversal of the partscan be accomplished and that changes "may'loe made which do not depart fromthe spirit of the invention as disclosed nor the scope thereof'asrdefined in the appended claims.

'Whatis claimed is:

fluid pres'sure actuated press having :a housing and a vertically reciprocableixram, :hori 'zontally spaced first and second fluidpressure'em' tensible devices connected to said' housingand -'saidram for reciprocatingsaid" ram; '-means"-for coordinating the'o'peration of said extensible'devices to provide for level uniform-travel of said ra n; said means inciuding" affir'st vertieai1y'ex.- tending"rack' connected tothe' ram adjacent'one 7 ndof the ramthereof for vertical movement with said ram, a second vertical rack horizontally spaced from said first rack, said second rack being independently supported relative to said ram adjacent a second end of said ram, a rotatable shaft Journalled on said housing, said shaft having rotatable members engaging said racks whereby during reciprocation of said ram said second rack is maintained in vertically coordinated relation with respect to said first rack; means for supplying fluid under pressure to said first and second fluid extensible devices, said last named means including first and second fluid pumps respectively communicating with said first and second exten sible devices, power means adapted to operate said pumps, first and second electrically controlled clutch means between first and second pumps and said powerimeans, and first and second switch means connected to said ram for reciprocation therewith and respectively connected to said first and second clutch means, saidv first and second switch means being individually engageable by saidsecond rack during tilting of one end of the ram with respect to the other end whereby said clutches are individually actuated in response to the switches to control the fluid delivery of said pumps to the extensible devices during unequal operation of one extensible device with respect to the other. c

- 2. A hydraulic press having a housing and a reciprocable ram, spaced first and second fiuid pressure extensible devices connected to said ram and said housing for reciprocating the ram; means for coordinating the operation of said extensible devices to provide for level uniform travel ofsaid ram, said means including a first rack secured to the ram for reciprocation therewith, a second rack laterally spaced from said first rack, said second rack being independently supported free of the ram whereby the ram is slidably movable in a vertical direction with respect to said second rack, a rotatable torque shaft journalled on the housing, said torque shaft including a first member connected to the torque shaft for rotation therewith, said first member engaging the first rack for rotating said torque shaft and a second member connected to said torque shaft for rotation therewith, said second member engaging said second rack for securing the same in substantially the same vertical position as said first rack during rotation of the torque shaft; means for supplying fluid under pressure to said extensible devices comprising first and second fluid pumps, the pumps having first and second delivery conduits respectively in communication with said first and second extensible devices, a first return conduit connecting the first extensible device with the second pump, a second return conduit connecting the second extensible device with the first pump, means for rotating said pumps comprising a power unit, first and second electrically controlled clutches respectively between the first and second pumps and said power unit, first and second switch means on said ram, and means connecting said switch means and said electrically controlled clutches, said switch means being individually engageable by said second rack during tilting movement of the ram for de-energizing one of said clutches thereby stopping fluid delivery of one of saidpumps to one of said extensible devices. said switch means being arranged and constructed to again energize said clutch during return of the ram to a level position.

3. A fluid pressure actuated press having a housing and a vertically reciprocable ram, horiac s- 4 zontally spaced first and second fluid pressure extensible devices connected to said housing and said ram for reciprocating said ram; means for coordinating the operation of said extensible devices to provide forlevel uniform travel of said ram, said means including a first rack connected to the ram adjacent one end thereof for reciprocation therewith, a second rack spaced from said first rack, said second rack being supported independently relative to said ram adjacent a second end of said ram, a rotatable shaft journalled on said housing, said shaft having pinions engaging said racks whereby during reciprocation of said ram said second rack is maintained in position with respect to said first rack; means for supplying fluid under pressure to said first and second fluid extensible devices, said means including first and second fluid pumps respectively communicating with said first and second extensible devices, power means adapted to operate said pumps, first and second electrically controlled clutch means between said first and second pumps and said power means, and first and second switch means connected to said ram for reciprocation therewith and respectively con nected to said first and second clutch means; said first and second switch means being individually cngageable by said second rack during tilting of one end of the ram with respect to the other end whereby said clutches are individually actuated in response to the switches to control the fluid delivery of said pumps to the extensible devices during unequal operation of one extensible device with respect to the other.

4. In a fluid pressure actuated press having a reciprocable ram, spaced first and second fluid pressure extensible devices connected to said ram for reciprocating the same, means for supplying fluid under pressure to said fluid extensible devices including a pump in communication with said fluid extensible devices; a leveling mechanism for coordinating the operation of said extenslble devices to provide for level uniform travel of the ram comprising, a first rack supported on the ram for reciprocation therewith, a second rack spacedly positioned with respect to said first rack, said second rack being positioned independently free of the ram whereby said ram may move relative to said second rack. a rotatable shaft stationarily positioned with respect to said ram, said shaft having a first member rotatable with said shaft engaging said first rack whereby said shaft is rotated during reciprocating movement of said ram and said first rack, said shaft having a. second member rotatable with said shaft engaging the second rack for maintaining said second rack in coordinated relation with respect to said first rack, a switch movable with said ram, means connecting said switch with said pump, and means on said second rack for engaging said switch during tilting movement of said ram, whereby said pump is controlled in response to said switch to regulate the fluid flow to one of said extensible device until level position of said ram is again established.

5. In a hydraulic press having a vertically reciprocable ram, spaced first and second hydraulic units connected to said ram for reciprocating the same, means for supplying fluid under pressure to said fluid hydraulic units including a pump in communication with said hydraulic units leveling mechanism for coordinating the operation of said hydraulic unltsto provide for level uniform travel of the ram comprising, a first rack supported on the ram for vertical reciprocation therewith, a second rack transversely spaced with respect to said first rack and substantially parallel thereto, said second rack being positioned free of the ram whereby said ram may move relative to said second rack, a rotatable shaft stationarily positioned with respect to said ram, said shaft having a first pinion engaging said first rack whereby said shaft is rotated during reciprocating movement of said ram and said first ram, said shaft having a second pinion engaging the second rack for maintaining said second rack in vertically coordinated relation with respect to said first rack, a switch mechanism means connect.- ing said switch mechanism with said pump, and means on said second rack for engaging said switch mechanism during tilting movement of said ram, whereby said pump is controlled to regulate the fluid flow to one of said hydraulic units until level position of said ram is again established.

6. In a hydraulic press having a housing and a vertically reciprocable ram, horizontally spaced first and second hydraulic units connected to said housing and said ram for reciprocating said ram; means for supplying fluid under pressure to said hydraulic units including first and second pumps, a power unit for operating said pumps, first and second electrically controlled clutches between the power units and said pumps; a leveling mechanism for coordinating the operation of said hydraulic units to provide for level uniform travel of said ram comprising, a first rack supported on the ram for reciprocation therewith, a second rack horizontally spaced from said first rack, said second rack being independently supported with respect to said ram, means for maintaining said first and second racks in horizontal spaced alignment during and second contact elements individually en-' gageable by said second rack during tilting of said ram for actuating either of said clutches thereby controlling operation of one of said pumps for regulating the delivery of fluid to one of said hydraulic units until level travel of said ram is established.

'7. In a fluid actuated press having a housing and a vertically reciprocable ram, horizontally spaced first and second hydraulic units connected to said housing and to said ram for reciprocating said ram; means for supplying fluid pressure to said hydraulic units including a pump structure, first and second conduits connecting said pump structure and said first and second hydraulic units; a leveling mechanism for coordinating the operation of said hydraulic units to provide for level uniform travel of said ram including a first rack connected to the ram for reciprocation therewith, a second rack supported independently of said ram, means for maintaining said first and second racks in horizontally aligned relation during movement of said ram including a rotatable member journalled on the housing, first and second pinions connected to said rotatable members for rotation therewith, said pinions engaging the racks whereby said rotatable member is rotated, and means connected to said pump structure and constructed and arranged for engaging the second rack during tilting of said ram to control said pump structure and the fluid delivery through one of said conduits to one of said hydraulic units until a level position of said ram is established.

8. For a movable reciprocating member having first and second spaced fluid pressure ex-'- tensible devices connected thereto and first and second fluid pressure actuators respectively connected to the first and second extensible devices; a leveling mechanism for coordinating the operation of the extensible devices comprising a first rack bar connected to the reciprocating member adjacent one end, a second rack bar horizontally spaced and connected to the reciprocating member adjacent a second end, said rack bar being supported independently of the ram, a rotating shaft including pinions engaging and coordi hating the position of said racks, and control means on the reciprocating member responsive to tilting uneven movement of said member for engaging the sliding rack thereby activating the control means for regulating the fluid pressure actuator to control the fiuid fiow to said extensible devices thereby coordinating the operation of said device.

9. In a reciprocating member as claimed in claim 8 wherein the control means includes a switch engaging-the sliding rack for controlling the fiuid pressure actuators. I p

10. In a reciprocating member according to claim 9 wherein the control means includes a pair of electrically controlled clutches and switch means mounted for reciprocation on said ram, said switch means being connected to said clutches, the clutches being adapted to control the fluid actuators, said clutches being responsive to the actuation of the switches for controlling the fiuid pressure actuators.

11. In a reciprocating member according to claim 18 wherein the first rack bar is pivotally connected to the ram whereby the first rack bar may be adjusted angularly. V

EDWARD M. DREIS.

REFERENCES CIIEfi The following references are of record in the 

